Steady rests



G. H. PQRATH Aug. 25, 1964 STEADY RESTS 5 Sheets-Sheet 1 Filed Dec. 15,1962 INVENTOR. GORC ON 1'7. PORH 7' BY y w,

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Aug. 25, 1964 G. H. PORATH STEADY RESTS 5 Sheets-Sheet 2 Filed Dec. 15,1962 BY 23% f d/K 4M Aug. 25, 1964 G. H. PORATH 3,145,513

STEADY RESTS Filed Dec. 15, 1962 5 Sheets-Sheet 3 I I i J 76 INVENTOR.GORDON 6'. Penn? w M A rro/e/vsrs Aug. 25, 1964 G. H. PORATH STEADYRESTS 5 Sheets-Sheet 4 Filed Dec. 13, 1962 IN VENTOR.

ATTORNEYS Aug. 25, 1964 PQRATH 3,145,513

STEADY RESTS Filed Dec. 13, 1962 5 Sheets-Sheet 5 INVENTOR 50x00 0'.POAPATH United States Patent 3,145,513 STEADY RESTS Gordon H. Porath,6101 Concord, Detroit, Mich. Filed Dec. 13, 1962., Ser. No. 244,467 28Claims. (Cl. 51-238) This invention relates to steady rests forrotatably supporting workpieces and particularly to steady rests forrotatably supporting engine camshafts in position for grinding.

One of the operations in the forming of engine camshafts is the grindingof the cam lobe surfaces of engine camshafts. At the present time, thisis accomplished in grinding machines which rotatably support the ends ofthe engine camshaft and drive the engine camshaft during the grinding.Steady rests in the form of mechanical bearing supports are provided forthe camshaft bearing surfaces at longitudinally spaced points along theengine camshaft for the two-fold purposes of first removing anydistortion in the axis of the engine camshaft which has been formedduring prior manufacturing steps and, second, holding the axis of thecamshaft as stable as possible during the grinding. It is not uncommonin such engine camshafts to find that the axis of the camshaft isdistorted in excess of 0.010 inch. The major disadvantage with themechanical steady rests presently used in such machines is that theyhave a metal-to-metal contact with the portions of the engine camshaftand thereby tend to wear necessitating their frequent repair andreplacement. In addition, any fiaw in the surfaces of the steady reststends to mar the contacted surfaces of the engine camshaft. Moreover,the bearing surfaces are often out of round or vary in diameter therebyintroducing additional inaccuracies.

It is therefore an object of this invention to provide an improvedsteady rest which will more effectively support the engine cam shaft andremove any distortion in the axis thereof.

It is a further object of this invention to provide such a steady restwhich will support the engin cam shaft without metal-to-metal contact inboth the static and rotary positions thereof.

It is a further object of this invention to provide such a steady restwhich utilizes a pressurized liquid from an external source as the loadsupporting medium between the steady rest and the workpiece.

It is a further object of this invention to provide such a steady restwhich will effectively support the workpiece at all speeds of rotation.

It is a further object of this invention to provide such a steady restwhich will utilize the same liquid as is used as a coolant in thegrinding operation.

It is a further object of this invention to provide a grinding machinearrangement including such steady rests wherein operation of the machineis prevented except where the workpieec is in position in the steadyrest.

It is a further object of this invention to provide a grinding machinehaving such steady rests wherein opera tion of the machine is preventedunless liquid is flowing to the steady rests.

It is a further object of this invention to provide an adjustable steadyrest which can be used for workpieces of varying diameters.

Basically, each steady rest which is associated with a machine includesan opening which is adapted to surround a portion of the workpiece suchas the engine cam shaft. A plurality of pressure pockets or pads areprovided around the opening and an orifice is associated with eachpressure pad. Liquid under pressure is provided to each orifice. Whenthe workpiece is placed in position in the steady rest and the liquid issupplied to the steady rest, a film of liquid flows continuously inlaminar fashion at 3,145,513 Patented Aug. 25, 1964 a low velocitybetween the adjacent surfaces of the steady rest and the workpiece insuch a manner that the liquid dissipates its pressure a short distancefrom the pressure pad. Any load or distortion on a workpiece causes theworkpiece to tend to move toward one pad or pads so that the flow ofliquid from the pad is restricted; since the liquid is being suppliedcontinuously in each pad, the pressure in the pads increases. At thesame time, the workpiece tends to move away from the opposite pad orpads opening or relieving the restriction to flow and the pressure inthe pad or pads decreases. A pressure differential is thus created whichmoves the workpiece to its centered position relative to the steadyrest. The cooperative action of a plurality of steady rests spacedlongitudinally along the engine shaft removes the distortion in theengine cam shaft and maintains the axis thereof in a stable position.Because there is never any metal-to-metal contact, there is no weareither on the steady rest or the workpiece.

In the drawings:

FIG. 1 is a fragmentary plan view of a grinding machine embodying theinvention.

FIG. 2 is a partly diagrammatic plan view of a modified form of grindingmachine.

FIG. 3 is a side elevation of one of the steady rests shown in FIG. 1.

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3.

FIG. 5 is an end view taken in the direction of the arrow 5 in FIG. 3.

FIG. 6 is a sectional view taken along the line 66 in FIG. 5.

FIG. 7 is an enlarged fragmentary part sectional view of a portion ofthe steady rest shown in FIG. 5.

FIG. 8 is. a schematic hydraulic and electrical diagram for the machineembodying the invention.

FIG. 8A is a fragmetary sectional view on an enlarged scale of a typicalcapillary tube used in the steady rests.

FIG. 9 is a side view of a modified form of steady rest.

FIG. 10 is a fragmentary sectional view on an enlarged scale taken alongthe line 1010 in FIG. 9.

FIG. 11 is a fragmentary perspective view of a part of the apparatusshown in FIGS. 9 and 10.

FIG. 12 is a partly diagrammatic view showing the manner in which thesteady rest shown in FIGS. 9-11 is used.

, FIG. 13 is a diagrammatic showing of the manner in which the pressurepads function in the steady rest embodying the invention.

Referring to FIG. 1, which shows a portion of a grinding machine, anengine cam shaft C having longitudinally spaced cam surfaces S which areto be ground is rotatably mounted between centers Ida and 10b of thegrinding machine. Center 10:: is driven and is provided with a pin whichengages an opening in the end of the camshaft to drive the camshaft. Thepin is non-circular so that only a rotational force is provided on thecamshaft. This is to accommodate any eccentricity between the center 10aand the opening in the camshaft. The above arrangement is conventional.

In order to support the engine camshaft intermediate its ends duringgrinding and to remove any distortion in the axis thereof during thegrinding, steady rests 11 are mounted at spaced points along the bed 12(FIG. 5) of the machine to support the engine camshaft C at thecylindrical bearing surfaces B.

Referring to FIGS. 1, 3-5, each steady rest 11 comprises a base 13 whichhas projections 14 at its ends Which receive bolts 15 which are threadedinto 'T-nuts 15a riding in a T-slot 15b in the bed 12. Base 13 alsoincludes a downwardly extending flange 16 adapted to engage the rearsurface 17 of the bed 12 and a downwardly extending flange 18 extendingalong the front surface of the bed 12. Locking screws 19 extend throughthe flange 18 (FIG. into engagement with a spacer block 20 and pressblock 20 against the front surface 21 of the bed 12 to lock the base 13in adjusted position on the bed 12. In this manner, each steady rest 11can be fixed at any point longitudinally on the bed 12.

Referring to FIGS. 37, each steady rest includes a primary slide 22which is slidably mounted on the flat upper surface of the face 13 andguided by keepers 13a. Provision is made for positively locking thehorizontal position of primary slide 22. on base 13 and includestriangular locking blocks 23 having inclined faces 24 which engage aninclined wall 25 projecting downwardly from the underside of a recess 26in the slide 22. Wall 25 is inclined or skewed with respect to the axisof movement of primary slide 22 on base 13. Each block 23 is held inadjusted position by a screw 24' threaded into the base and engaging theblock 23. By moving the blocks into contact with the inclined Wall 25,the blocks are positioned to lock the wall and, in turn, the primaryslide 22 in position. A lock or jam nut 2601: each screw 24' holds theblocks in adjusted position. By this arrangement, the steady rests 11are adjusted and locked in and out horizontally of bed 12 transverselyof the axis of the workpiece.

A secondary slide 30 is slidably mounted on an inclined face 32 of theprimary slide 22 and guided by keepers 31 in order to provide forvertical adjustment of the steady rest. The slide 30 is locked inposition on the surface 32 by an arrangement which includes triangularblocks 33 which engage a skewed or inclined wall 34 and are adjusted byscrews 35 held in adjusted position by lock nuts 36 in a manneridentical to the manner of locking of the primary slide 22 on the base13.

A pair of separable or partible sections 40, 41 are provided on thesecondary slide 30. Section 40 forms a part of the slide 30;. The uppersection 41 is hinged to the lower section 40 along the longitudinal axisof the machine parallel to the axis of the workpiece or cam shaft by apin 42 which extends through an opening in the section 41.

Sections 40, 41 are formed with mating surfaces 44, 45 and interengagingregistering grooves 47 and teeth 46. The opposed surfaces 44, 45 areformed with semi-cylindrical surfaces 48, 49 which define an opening 50that is adapted to surround one of the bearing B of the cam shaft C.

Referring to FIGS. 4 and 8A, the surfaces 48, 49 are formed withcircumferentially spaced pockets or pressure pads 51. Each pressure pad51 comprises a recess in its corresponding surface to which liquid issupplied at a predetermined pressure. An orifice formed by a capillarytube 53 is provided for each pressure pad 51. The capillary tube 53 isset in a-set screw 54 threaded into an opening 55 that communicates withthe pad 51. The end 56 of the screw includes an Allen head depression 57for engagement by a tool. O-ring 58 provides a seal.

Hydraulic fluid under pressure from an external source is provided tothe pressure pads 51 on the lower section 40 through an inlet 59 topassageway 60 and branch passages 61, 62, 63. Similarly, liquid issupplied to the pressure pads 51 of the upper section 41 through aninlet 64, drilled passageways 65, 66 and branch passages 67, 68.

Any viscous liquid, such as machine oil, may be used. However, in thecast of a grinding machine, it is preferred that the liquid comprise thesame coolant that is used in grinding, such as a water soluble oil orwaxed based fluid in water.

The liquid supplied to the inlets 59, 64 is at substantiallypredetermined constant volume-and pressure. The orifices for eachpressure pad are selected in such a manner that in each particularsteady rest the pressures in the pressure pads are'equal.

When a steady rest is placed in position and the sections 40, 41 arebrought into mating relation, a laminar film of liquid flowscontinuously at low velocity between the surfaces 48, 49 of the sections40, 41 and the surface of the engine cam shaft and the adjoiningsurfaces and the pres sure of the liquid drops to zero as it leaves thesurfaces 48, 49. The number and size of the pressure pads 51 is such asto provide a force sufiicient to support the engine cam shaft andmaintain its axis stable.

The size of the opening 50 defined by the surfaces 48, 49 is so adjustedrelative to the surface of the engine cam shaft which is surrounded bythe sections 40, 41 that a thin film of liquid flows at all times inlaminar fashion at low velocity between the surfaces and preferably substantially all the pressure of the liquid is dissipated by the time theliquid has passed from the pad to the periphery of the surface inquestion.

The space between the surfaces of opening 50 and the bearing surface Bmay range between two-thousandths (0.002) of an inch and oneten-thousandth (0.0001) of an inch and preferably between one-thousandth(0.001) of an inch and one ten-thousandth (0.0001) of an inch. Althoughit is preferred that the space be the same around the opening, anyinaccuracies due to out of round condition of the bearing surface of theworkpiece will be compensated for provided at least some portions definea space within the above limits.

Since each of the steady rests tends to retain the portion of the enginecamshaft centered and stable relative to the steady rests, if theopenings 50 of succeeding steady rests are accurately aligned, thesteady rests will remove any distortion in the axis of the enginecamshaft.

The provision of low velocity laminar flow of liquid between thesurfaces of the sections 40, 41 and the engine camshaft effectivelyeliminates any friction because there is no metal-to-metal contact. Theforce required to remove any distortion in the engine camshaft and theforces on the engine camshaft during the grinding are compensated for bythe flow through the pressure pads thereby maintaining a stable accurateaxis for the engine camshaft. Any minor surface or machininginaccuracies in the surfaces 48, 49 or the adjacent surface of theengine camshaft do not adversely affect the action and the fullycompensated fiow accommodates for such surface or machining inaccuraciesproducing an ultra-precise, stable, smooth, vibration-free axis for theengine camshaft.

FIG. 8 represents a combined hydraulic and electrical circuit for theapparatus. As shown, a pump driven by an electric motor 81 suppliesliquid through a line 82 and line 83 through a filter 84 which may be ofthe type that has an indicator switch in the event that the liquid hasparticles of excessive size therein. The liquid then passes through line85 through a one-way valve 86 to the steady rests 11 represented byblocks in FIG. 8. Since the liquid preferably is the same as the liquidcoolant used in the grinding operation, it is returned through thecentral collecting system through a control valve 87 and filter 88 whichmay be of the endless fabric type and micronic filter 89 similar tofilter 84 to the inlet of the pump 80.

When an operator places an engine camshaft in the machine and thesections 40, 41 of the steady rest are closed, switches 74 are alsoclosed. These switches 74 are shown more specifically in FIG. 1 andcomprise plungers 91 that are actuated by eccentric 75. When theoperator then depresses the master switch 93 (FIG. 8), power is suppliedto a vent valve 94 that prevents the normal flow of fluid from line 82through line 95 to line 95' and permits the fluid then to flow through aline 83 and 85 to the steady rests. A pressure relief valve 96 isprovided in the line 95. When the pressure in the line 85 builds up tothe desired pressure when the steady rest sections are fully closed, apressure switch 97 is actuated to supply power to the motor 98 fordriving the grinding machine.

By this arrangement, the switches 74 prevent the application of liquidto the steady rests until the steady rests are being closed and thepressure switch 97 prevents operation of the grinding machine until theliquid is flowing at the predetermined pressure. As a result, themachine will not operate until the pressure pads are functioningproperly to form the desired support for the engine camshaft.

The manner of operation of the steady rests can be more readilyunderstood by referring to FIG. 13 which represents the relativearrangement provided by the pressure pads 51. In the event that a forceis applied to the engine camshaft by the load of the grinding wheel orif a distortion of a portion of the engine crankshaft tends to be out ofalignment with the axis of the opening 50 of the steady rest when theengine camshaft is first placed in the steady rest, the pressure in thepad 51 represented by the arrow P increases because of the restrictingaction and the pressure in the opposed pad represented by the arrow Pdecreases because of the unrestricting action so that a force is appliedon the engine camshaft upwardly tending to return the engine camshaft toits initial position. Because the steady rests are designed withinternal supporting pressures far in excess of applied loads and becauseof the minute clearance dimensions, it can readily be tmderstood thatthe relative movements herein described are very slight. In fact, themovements are so slight that they cannot be measured.

A steady rest embodying the invention provides a very accurate controlof the axis of the workpiece which is supported and since there is nowear the accuracy is maintained indefinitely. The steady rest hassubstantial load carrying characteristics to make it resistant to shockso that it can be used without damage for prolonged periods.

In order to insure that dirt and other cuttings from the grindingoperation do not contact the surfaces of the teeth and grooves 46, 47,passages 7G 73 are provided which supply liquid under pressure to thesurfaces of teeth 46 as the sections 41, 42 are closing. A switch 74- isprovided adjacent the support and is actuated by an eccentric 75 on pin42 to initiate passage of the fluid just prior to the full closing ofthe sections 41, 42.

In order to insure locking of the sections, a U-shaped yoke 76 ispivoted to a pin 77 on the fixed slide 30 and is provided with a handle78 so that it can be readily swung to bring transversely curved surface79 of the bight portion thereof into overlying relation with a flatincline 80 on the section 41 and thereby lock the section 41 inposition. This provides a means for readily locking the sections 40, 41together. The interengaging teeth 46 and grooves 47 provide for absoluteregistration of sections 49, 41 so that the steady rest is not affectedby any wear in the hinge and particularly pin 42 due to opening andclosing.

In the form of the invention shown in FIGS. 9-12, a universal steadyrest is provided for rotatably supporting the end of a workpiece W whichis held in a chuck as shown in FIG. 12. The steady rest comprises twopivoted sections 101, 102 which are connected and hinged to one anotherby a pin 103, locked and closed by a pivoted bolt 104 and nut 105. Thelower section 192 is mounted on the bed of the machine and provided witha pair of adjustable radially movable pad members 1596 while the uppersection 1431 is provided with one radially movable pad member 106. Asshown in FIG. 10, each pad member comprises a pad body 197 which ismovable radially in an opening in the section and held in lockedposition radially by a screw 103. Each body 107 includes an axialopening 109 into which a screw 110 is threaded. The screw 119 supports,as by silver soldering, a capillary tube 111 to provide an orifice. Thelower end of the body is formed with a pressure pad 112 (FIG. 11).Liquid is supplied by a flexible tube 113 to the passage to provideliquid to the orifice and, in turn, the pressure pad 112. A secondpassage 114 extends axially of the body and is connected to a gauge 115(FIG. 9).

In practice, the workpiece is initially positioned with the aid of amicrometer indication. The steady rest is then brought in position. Thefluid flow is initiated and the bodies 107 are adjusted radiallyinwardly and out-. wardly until the pressures indicated by the gaugesare equal. This will indicate that the workpiece W is being heldcentrally. When the pressures have been made equal, the workpiece W isrotated by hand and the adjustment of the screws 168 is continued untilthere is no change in pressure as the workpiece W is rotated. At thesame time, the micrometer indicator is used to check alignment with thecenter of the chuck. In this manner, the end of the workpiece isadjusted so that it will be thereafter supported in a stable,frictionless manner during rotation thereof by the chuck 118 (FIG. 12).

In the form of the invention shown diagrammatically in FIG. 2, foursteady rests are provided. The centers 10a, 10b are eliminated, theentire weight of the camshaft being supported by the steady rests andthe pin serving to rotate the camshaft at the proper speed for beingworked on. Only limit stops 116, 117 are provided to prevent axialmovement of the workpiece but do not support any load. By this modifiedarrangement, in addition to the advantages heretofore mentioned,inaccuracies due to the hearings in the tailstock and headstock whichwould be introduced by the centers are entirely eliminated. In addition,any error due to misalignment of the centerdrilled on the ends of theworkpiece with respect to the center of the bearings B is entirelyeliminated. Finally, the camshaft is supported during grinding in theidentical manner that it will be used in the engine, that is, at thebearings thus further increasing the accuracy of the grinding of thecamshaft.

. I claim: a

1. In a grinding machinefor grinding the surfaces of an engine camshaftor the like, the combination comprismg a grinding machine,

a plurality of steady rests positioned on said machine for supportingthe engine camshaft at longitudinally spaced points during grinding, 1

each ,said steady rest having a cylindrical opening adapted to receiveand surround a portion of said engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

and means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the being equal,

such that when an engine camshaft is placed in position with the openingsurrounding said portions of the cam shaft, a pressurized film of liquidflows continuously through the pressure pads between the surfacesdefining the opening and the surfaces of theportions of the enginecamshaft surrounded thereby so that forces are applied to the enginecamshaft to remove any axial distortion therein and maintain the axis ofthe engine camshaft in a stable position relative to the steady rest.

2. The combination set forth in claim 1 wherein said liquid comprisesthe grinding coolant,

means for collecting said coolant the steady rest,

and means for filtering the coolant after it is collected and before itis returned to the steady rest.

3. The combination set forth in claim 1 wherein the orfice of each saidpressure pad is positioned in its corresponding steady rest.

4. The combination set forth in claim 1 wherein each said steady restcomprises separable sections which are partible to facilitate theinsertion of the engine camshaft.

5. The combination set forth in claim 1 wherein each said steady restincludes means for adjusting said steady pads of each steady rest andreturning it to J rest vertically and horizontally relative to thegrinding machine.

6. In a grinding machine for grinding the surfaces of an engine camshaftor the like, the combination comprising a grinding machine,

a plurality of steady rests mounted at longitudinally spaced points onsaid machine for supporting the intermediate longitudinally spacedportions of the engine camshaft,

each said steady rest comprising separable sections which are adapted topart and receive the engine camshaft,

each said section having a surface cooperating to form a cylindricalopening for receiving and surrounding a portion of the camshft,

said surfaces of said sections being formed with circumferentiallyspaced pressure pads,

an orifice in said corresponding sections associated with each pressurepad,

means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the pads of each said steady rest being equal,

such that a pressurized film of liquid flows continuously between thesurfaces of each said steady rest and the corresponding portion of theengine camshaft so that forces are applied to the engine cam shafttending to hold the engine camshaft in a stable position relative to itssteady rest and removing any distortion of the engine camshaft.

7. The combination set forth in claim 6 including means for locking saidseparable sections in closed position.

8. The combination set forth in claim 6 wherein said separable sectionsare mounted on a base,

said base being adjustable horizontally of the machine.

9. The combination set forth in claim 8 including a support on saidbase,

said partible sections being mounted on said support,

said support being adjustable vertically relative to said base.

10. The combination set forth in claim 8 wherein said base is providedwith an inclined plane,

said support being mounted on said inclined plane and movable relativethereto,

means for locking saidsupport in adjusted position on said inclinedplane,

thereby providing vertical adjustment of said support relative to saidbase.

11. The combination set forth in claim 6 wherein said sections. of saidsteady rest are hinged about an axis parallel to the longitudinal axisof the grinding machine.

12. In a grinding machine for grinding the surfaces of an enginecamshaft or the like, the combination comprismg a grinding machine,

a plurality of steady rests positioned on said machine for supportingthe engine camshaft at longitudinally spaced points during grinding,

means engaging and driving the camshaft,

each said steady rest having a cylindrical opening adapted to receiveand surround a portion of said engine camshaft,

each said steady rest comprising partible sections which are partible tofacilitate the insertion of the engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the pads of each steady rest being equal,

such that when an engine camshaft is placed in position k with thebearing opening surrounding the portions of the camshaft, a pressurizedfilm of liquid flows continuously between the surfaces defining theopening and the surfaces of the engine camshaft surrounded therebythrough the pressure pads so that forces are applied to the enginecamshaft to remove any axial distortion therein and maintain the axis ofthe engine camshaft in a stable position relative to the steady rest,

and means responsive to the how of pressurized fluid to the orifices ofthe steady rest for controlling the operation of the drive means fordriving the engine camshaft.

13. In a grinding machine for grinding the surfaces of an enginecamshaft or the like, the combination comprising a grinding machine,

a plurality of steady rest positioned on said machine for supporting theengine camshaft at longitudinally spaced points during grinding,

each said steady rest having a bearing opening adapted to receive andsurround a portion of said engine camshaft,

each said steady rest comprising partible sections which are partible tofacilitate the insertion of the engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the pads of each steady rest being equal,

such that when an engine camshaft is placed in position with the bearingopening surrounding the portions of the camshaft a pressurized film ofliquid flows continuously between the surfaces defining the opening andthe surfaces of the engine camshaft surrounded thereby through thepressure pads so that forces are applied to the engine camshaft toremove any axial distortion therein and maintain the axis of the enginecamshaft in a stable position relative to the steady rest,

and means responsive to the positioning of the engine camshaft in thesteady rests for controlling the flow of liquid to the steady rests.

14. The combination set forth in claim 13 including means for engagingand driving the camshaft,

a switch responsive to the flow of pressure in the hydraulic circuit ofthe steady rests and electrically conneoted to the drive mechanism forthe grinding machine whereby the grinding machine will only be energizedwhen liquid is flowing to the steady rests at the proper supportpressure.

15. In a machine for rotatably supporting a workpiece,

the combination comprising a machine,

a plurality of steady rests positioned on said machine for supportingthe workpiece at longitudinally spaced points,

each said steady rest having an opening adapted to re ceive and surrounda portion of said workpiece,

each said steady rest comprising partible sections which are partible tofacilitate the insertion of the engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the pads of each steady rest being equal,

such that when said workpiece is placed in position with the openingsurrounding said portions of the workpiece, a pressurized film of liquidflows continuously through the pressure pads between the surfaces defining the opening and the surfaces of the engine camshaft surroundedthereby so that forces are applied to the engine camshaft to remove anyaxial distortion therein and maintain the axis of the engine camshaft ina stable position relative to the steady rest.

16. The combination set forth in claim wherein the orifiw of each saidpressure pad is positioned in its corresponding steady rest in closeproximity to said part.

17. The combination set forth in claim 15 wherein each said steady restincludes means adjusting said steady rest vertically and horizontallyrelative to the machine.

18. The combination set forth in claim 15 including means for lockingsaid separable sections in closed position.

19. The combination set forth in claim 15 wherein said separablesections are mounted on a base,

said base being adjustable horizontally of the machine.

20. The combination set forth in claim 19 including a support on saidbase,

said partible sections being mounted on said support,

said support being vertically adjustable relative to said base.

21. The combination set forth in claim 20 wherein said base is providedwith an inclined plane,

said support being mounted on said inclined plane and movable relativethereto,

means for locking said support in adjusted position on said inclinedplane,

thereby providing the vertical adjustment of said support relative tosaid base. 22. The combination set forth in claim 15 wherein saidsections of said steady rest are hinged about an axis parallel to thelongitudinal axis of the grinding machine. 23. The combination set forthin claim 15 including means responsive to the positioning of the enginecamshaft in the steady rests for controlling the flow of liquid to thesteady rests.

24. In a machine for rotatably supporting a workpiece, the combinationcomprising a machine, a steady rest positioned on said machine forsupporting the workpiece at a point along its length,

said steady rest having a cylindrical opening adapted to receive andsurround a portion of said workpiece.

each said steady rest comprising partible sections which are partible tofacilitate the insertion of the engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

means for supplying liquid under pressure to each said the pressure ofliquid in the pads of each steady rest being equal,

such that when said workpiece is placed in position with the openingsurrounding said portion of said workpiece a pressurized film of liquidflows continuously through the pressure pads between the surfacesdefining the opening and the surface of said workpiece surroundedthereby so that forces are applied to the workpiece to maintain the axisof said workpiece in a stable position relative to the steady rest.

25. In a machine for rotatably supporting a workpiece, the combinationcomprising a machine,

a steady rest mounted on said machine for rotatably supporting a portionof the workpiece,

said steady rest comprising separable sections which are adapted to partand receive the workpiece, said section supporting radially movablebodies having surfaces cooperating to define portions of a cylinder forreceiving and surrounding a portion of the worlo piece, the surfaces ofsaid bodies being formed with circum ferentially spaced pressure pads,

an orifice in the corresponding body associated with each pressure pad,

means for supplying liquid under pressure to each said the pressure ofliquid in the pads of each said steady rest being equal,

such that a pressurized film of liquid flows continuously between thesurfaces of said steady rest and the corresponding portion of theworkpiece so that forces are applied to the workpiece tending to holdthe worlo piece in a stable position relative to its steady rest.

26. The combination set forth in claim 25 wherein said sections of saidsteady rest are hinged about an axis parallel to the longitudinal axisof the grinding machine.

27. The combination set forth in claim 25 including a pressure gaugemounted on each said body and communicating with the pressure pad ofsaid body.

28. In a grinding machine for grinding the surfaces of an enginecamshaft or the like, the combination compris mg a grinding machine,

a steady rest positioned on said machine for supporting the enginecamshaft during grinding,

said steady rest having a cylindrical opening adapted to receive andsurround a portion of said engine cam shaft,

each said steady rest comprising partible sections which are partible tofacilitate the insertion of the engine camshaft,

said steady rest having a plurality of circumferentially spaced pressurepads about said opening,

an orifice associated with each pressure pad,

and means for supplying liquid under pressure to each said orifice,

the pressure of liquid in the pads of said steady rest being equal,

such that when an engine camshaft is placed in position with the openingsurrounding said portions of the camshaft, a pressurized film of liquidflows continuously through the pressure pads between the surfacesdefining the opening and the surfaces of the portions of the enginecamshaft surrounded thereby so that forces are applied to the enginecamshaft to remove any axial distortion therein and maintain the axis ofthe engine camshaft in a stable position relative to the steady rest.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A GRINDING MACHINE FOR GRINDING THE SURFACES OF AN ENGINE CAMSHAFT OR THE LIKE, THE COMBINATION COMPRISING A GRINDER MACHINE, A PLURALITY OF STEADY RESTS POSITIONED ON SAID MACHINE FOR SUPPORTING THE ENGINE CAMSHAFT AT LONGITUDINALLY SPACED POINTS DURING GRINDING, EACH SAID STEADY REST HAVING A CYLINDRICAL OPENING ADAPTED TO RECEIVE AND SURROUND A PORTION OF SAID ENGINE CAMSHAFT, SAID STEADY REST HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED PRESSURE PADS ABOUT SAID OPENING, AN ORIFICE ASSOCIATED WITH EACH PRESSURE PAD, AND MEANS FOR SUPPLYING LIQUID UNDER PRESSURE TO EACH SAID ORIFICE, THE PRESSURE OF LIQUID IN THE PADS OF EACH STEADY REST BEING EQUAL, SUCH THAT WHEN AN ENGINE CAMSHAFT IS PLACED IN POSITION WITH THE OPENING SURROUNDING SAID PORTIONS OF THE CAM SHAFT, A PRESSURIZED FILM OF LIQUID FLOWS CONTINUOUSLY THROUGH THE PRESSURE PADS BETWEEN THE SURFACES DEFINING THE OPENING AND THE SURFACES OF THE PORTIONS OF THE ENGINE CAMSHAFT SURROUNDED THEREBY SO THAT FORCES ARE APPLIED TO THE ENGINE CAMSHAFT TO REMOVE ANY AXIAL DISTORTION THEREIN AND MAINTAIN THE AXIS OF THE ENGINE CAMSHAFT IN A STABLE POSITION RELATIVE TO THE STEADY REST. 